Evaluation of total muscular activity by quantification of electromyograms through a summing amplifier

In the present investigation a method of quantifying electromyograms (EMG's) from different muscle groups of the body to evaluate total muscular activity is described. A unipolar pickup, i.e., one standard silver cup surface electrode over each active muscle, was used because the EMG outputs with this electrode configuration during the same muscular activity were found to be greater than those with a bipolar pickup, i.e., two electrodes over each muscle. It was observed that for the purpose of quantification the root mean square (r.m.s.) value of a ‘steady’ level or the average r.m.s. value of a varying level of EMG is related in a linear fashion to the absolute mean value of the wave obtained by integrating the EMG for a specified time interval after making the waveform unidirectional. A similar relationship was observed with different voltage levels from a noise generator which was used for calibration purposes. EMG's from different muscle groups during isometric as well as isotonic voluntary contractions were found to summate together outside the body in a manner similar to noise voltages, i.e., the r.m.s. value of the combined voltages is equal to the square root of the sum of the mean square values of the individual waves. A method of passing EMG's through a summing amplifier and then quantifying the output for the evaluation of total muscular activity was developed, which greatly reduces the system components normally necessary for such studies. The results obtained from a series of experiments are discussed in detail.     

The effects of antioxidant supplementation during Percoll preparation on human sperm DNA integrity

The integrity of sperm DNA is crucial for the maintenance of genetic health. A major source of damage is reactive oxygen species (ROS) generation; therefore, antioxidants may afford protection to sperm DNA. The objectives of the study were, first, to measure the effects of antioxidant supplementation in vitro on endogenous DNA damage in spermatozoa using the single cell gel electrophoresis (comet) assay and, second, to assess the effect of antioxidant supplementation given prior to X-ray irradiation on induced DNA damage. Spermatozoa from 150 patients were prepared by Percoll centrifugation in the presence of ascorbic acid (300, 600 microM), alpha tocopherol (30, 60 microM), urate (200, 400 microM), or acetyl cysteine (5, 10 microM). DNA damage was induced by 30 Gy X-irradiation. DNA strand breakage was measured using the comet assay. Sperm DNA was protected from DNA damage by ascorbic acid (600 microM), alpha tocopherol (30 and 60 microM) and urate (400 microM). These antioxidants provided protection from subsequent DNA damage by X-ray irradiation. In contrast, acetyl cysteine or ascorbate and alpha tocopherol together induced further DNA damage. Supplementation in vitro with the antioxidants ascorbate, urate and alpha tocopherol separately has beneficial effects for sperm DNA integrity.      

Peripheral blood and synovial fluid T cells differ in their response to alloantigens and recall antigens presented by dendritic cells.

Properties of T cells from inflammatory lesions were analysed by comparing the response of peripheral blood (PB) and synovial fluid (SF) T cells from 19 patients with a range of arthropathies to enriched allogeneic dendritic cells (DC) in a primary mixed leucocyte reaction (MLR). In 17 patients the proliferative response of SF T cells was significantly (P less than 0.05) less than that of PB lymphocytes. The reduced response of SF T cells was observed in all disease categories studied and could not be attributed to differences in cell number requirements or response kinetics. Addition of recombinant interleukin-2 enhanced the response of SF T cells in a dose-dependent manner. Cell mixing experiments suggested that active suppression was not the underlying mechanism of the poor MLR response of SF T cells. In contrast to the MLR response. SF T cells were able to mount vigorous proliferative responses to recall antigen presented by autologous antigen-presenting cells. The possibility is discussed that T cells compartmentalized at inflammatory lesions are a unique population with a diminished ability to interact with DC and respond to primary stimuli but an ability to respond to secondary antigenic challenge.     

Phagosomal processing of Mycobacterium tuberculosis antigen 85B is modulated independently of mycobacterial viability and phagosome maturation

Control of Mycobacterium tuberculosis infection requires CD4 T-cell responses and major histocompatibility complex class II (MHC-II) processing of M. tuberculosis antigens (Ags). We have previously demonstrated that macrophages process heat-killed (HK) M. tuberculosis more efficiently than live M. tuberculosis. These observations suggested that live M. tuberculosis may inhibit Ag processing by inhibiting phagosome maturation or that HK M. tuberculosis may be less resistant to Ag processing. In the present study we examined the correlation between M. tuberculosis viability and phagosome maturation and efficiency of Ag processing. Since heat treatment could render M. tuberculosis Ags more accessible to proteolysis, M. tuberculosis was additionally killed by antibiotic treatment and radiation. Processing of HK, live, radiation-killed (RadK), or rifampin-killed (RifK) M. tuberculosis in activated murine bone marrow macrophages was examined by using an I-A(b)-restricted T-cell hybridoma cell line (BB7) that recognizes an epitope derived from Ag 85B. Macrophages processed HK M. tuberculosis more rapidly and efficiently than they processed live, RadK, or RifK M. tuberculosis. Live, RadK, and RifK M. tuberculosis cells were processed with similar efficiencies for presentation to BB7 T hybridoma cells. Furthermore, phagosomes containing live or RadK M. tuberculosis expressed fewer M. tuberculosis peptide-MHC-II complexes than phagosomes containing HK M. tuberculosis expressed. Since only live M. tuberculosis was able to prevent acidification of the phagosome, our results suggest that regulation of phagosome maturation does not explain the differences in processing of different forms of M. tuberculosis. These findings suggest that the mechanisms used by M. tuberculosis to inhibit phagosomal maturation differ from the mechanisms involved in modulating phagosome Ag processing.     

A test of the assumptions of the transtheoretical model in a post-traumatic stress disorder population

Prior reports suggest an ambivalence regarding treatment in individuals with Post-Traumatic Stress Disorder (PTSD). A model that accommodates such ambivalence is the Transtheoretical Model of Behavior Change (TTM, also known as the Stages-of-Change Model). Fifty veterans presenting for treatment completed self-report measures (94% response rate) that assessed disorder variables and constructs relating to the TTM. While the relationships between the components of each specific construct were found to be consistent with the findings of other studies and a number of predicted relationships between variables were confirmed, many results were inconsistent with the TTM. Notwithstanding questions about the suitability of the self-report measures, the unique characteristics of the veteran sample and the small sample size, the results suggest that the assumptions of the TTM were not met in veterans with PTSD. Copyright © 2005 John Wiley & Sons, Ltd.     

Molecular Analysis of Fiji Disease Fijivirus Genome Segments 1 and 3

Fiji disease fijivirus (FDV) genomic segments 1 (S1) and 3 (S3) were completely sequenced. FDV S1 comprised 4532nt and was predicted to encode a 170.6kDa protein. FDV S3 comprised 3623nt and was predicted to encode a 135.5kDa protein. The terminal sequences of S1 and S3 were 5 AAGUUUUU......CAGCUAGCGUC 3 and 5 AAGUUUUU......CAGCAGAUGUC 3, respectively, and located immediately adjacent to these sequences were 12bp imperfect inverted repeats. The predicted translation product of FDV S1 showed highest similarity to Rice black-streaked dwarf virus (RBSDV) S1 and is thought to encode the viral RNA-dependent RNA polymerase (RdRp). The predicted translation product of FDV S3 was found to be most similar to RBSDV S4 which is thought to encode the 'B-spike' protein. The FDV sequence contained an ATP/GTP binding motif and a leucine zipper motif, but these motifs were not found in the RBSDV sequence. Phylogenetic analysis based on the amino acid sequences of the RdRp of FDV S1 and other reoviruses revealed that the fijiviruses form a cluster close to the oryzaviruses. The RdRp sequences were grouped into genera that were consistent with the current reovirus classification scheme that is based on physico-chemical and biological properties.     

Biotyping of Escherichia coli by a simple multiple-inoculation agar plate technique.

A nine-test system using multiple-inoculation agar plates for biotyping of Escherichia coli is described. Testing of 959 strains resulted in 78 biotypes. On repeated testing, 96% of 182 strains had identical biotypes or differed by only one test. This system provides satisfactory differentiation among strains and is reproducible. Precise standardization of inoculum size is not required. Multiple inoculation allows time and cost-efficient testing of large numbers of strains.     

Elderly peoples' experiences of discharge from hospital.

In a study of patients' perceptions of the transition from hospital to the community, 115 elderly people registered with a central London group practice were interviewed shortly after they arrived home. Many patients received little notice of discharge, a third being told on the day they left the hospital. A third felt they had been discharged too soon and those living alone were significantly less likely to return to a heated home containing basic items of food. Seventy-seven patients, including 80% of those living alone were visited by family, friends or professionals within three days of coming home. Eighty-six per cent of non-professional visitors were women. Several of the elderly couples appeared to be under considerable stress and not all individuals were receiving the help they considered most appropriate to their needs. Many of the problems identified were due to poor communication between practice, hospital and patients. We suggest several measures aimed at improving the quality of that communication, so as to ensure that available resources can be mobilized to support this vulnerable group of people.     

Comparison of agar disk diffusion, microdilution broth, and agar dilution for testing antimicrobial susceptibility of coagulase-negative staphylococci.

A collection of 120 oxacillin-susceptible and 120 oxacillin-resistant coagulase-negative staphylococci (CNS) from six tertiary care hospital laboratories were tested by agar disk diffusion, three microdilution broth systems (Sensititre, Dynatech, and Alpkem), and the Vitek AutoMicrobic system for comparison with reference agar dilution results. The antimicrobial agents tested were oxacillin, cefazolin, cefotaxime, cefuroxime, cefamandole, fusidic acid, rifampin, and vancomycin. Incubation was at 30 or 35 degrees C for 24, 48, and 72 h. The broth media were supplemented with 2% NaCl for some antimicrobial agents, and the agar dilution method was used with and without the addition of 4% NaCl. The CNS were identified to species by the method of Kloos and Schleifer. The results showed a lack of concordance between two hospitals with respect to oxacillin susceptibility testing by agar dilution with no NaCl supplement. The reasons are not clear but may be related to variations in media. The 4% NaCl supplement or extended incubation to 48 h eliminated this difference. The cefazolin and cefotaxime susceptibility results in the agar disk diffusion test were unreliable if accepted at face value. Cefamandole testing correlated well with the reference method regardless of the method used, and salt supplementation is not recommended. Most of the oxacillin-resistant CNS were resistant to the other beta-lactam drugs except cefamandole. Of 22 CNS resistant to cefamandole, 21 were S. haemolyticus.